From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.switch.ch (mx2.switch.ch [85.235.88.33]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id DBF5B3B2A4 for ; Tue, 5 Oct 2021 17:43:40 -0400 (EDT) X-Virus-Scanned: by SpamTitan at switch.ch DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=switch.ch; s=selector1; t=1633470218; bh=3Sv90TNhwBNXhs2ZS9AWU5v7uSB/joEU5YHspoq5h8g=; h=From:To:Subject:In-Reply-To:References:Date; b=JHKsMwPyEamTejzc+d+sVp6staRDbS/1JtRRKxplFCBMCrYdFZSn26YhmcE+LIRdc X5KNTkHmHEasqfOLgboX1fET7ZrZ7iMK9iF86PDbJ4fq4udwAiwbuN8+QL7p+lts5S CgBVA7D2fRtcnt9+ECqmQR1qobbEluHnzHTm2g6oPICMbFk7KODQMu6VFZRV5IEku+ 1VNcAdUglccycj/PgVKpsx76dGHiBMygrI39wKfaqbLU9bWDoQA1GDPCJxgblnUody R8a+I4MSw0ZhdRxpLHRI6TqQE3Z1Qfwx2/xwZ6D1UAg0le/aLqy0LrnVBdsl9DG9p9 ZlyVOYXyimI5Q== Authentication-Results: mx2.switch.ch; x-trusted-ip=pass Received: from SWH-S04-EXC2.swd.switch.ch (unknown [172.16.60.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx2.switch.ch (Postfix) with ESMTPS id B74D8857BBC for ; Tue, 5 Oct 2021 23:43:32 +0200 (CEST) Received: from macsl (172.16.60.33) by SWH-S04-EXC2.swd.switch.ch (172.16.60.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.922.13; Tue, 5 Oct 2021 23:43:21 +0200 From: Simon Leinen To: Christoph Paasch via Rpm In-Reply-To: (Christoph Paasch via Rpm's message of "Tue, 05 Oct 2021 09:18:55 -0700") References: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (darwin) Date: Tue, 5 Oct 2021 23:43:20 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [172.16.60.33] X-ClientProxiedBy: SWH-S05-EXC3.swd.switch.ch (172.16.60.14) To SWH-S04-EXC2.swd.switch.ch (172.16.60.12) Subject: Re: [Rpm] Outch! I found a problem with responsiveness X-BeenThere: rpm@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: revolutions per minute - a new metric for measuring responsiveness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Oct 2021 21:43:41 -0000 Hallo Christoph, > That's right. BB is a transient problem that is extremely short-lived. > Having tried for the past year to reliably demo the user-visible > impact of bufferbloat, I have learned two things: > 1. When it happens, it is bad - really bad. > 2. However, it is very difficult to trigger it "on-demand". I seem to be able to trigger it quite reliably by using mobile data while traveling on the train and doing normal remote work. Here in Switzerland I often see RTTs in excess of 10 seconds. In France I have seen more than two MINUTES. Maybe I should start setting up systematic measurements. For example, if I just sent pings both from my laptop to a well-connected fixed host, and vice-versa, while capturing all ICMP packets on both ends, I should be able to learn about bufferbloat in both directions. It would be even better to have this in a mobile (web) app that could record/send location data from the mobile node, to spot the regions (presumably around tunnels and other connectivity-challenged areas) where the problem tends to occur most often. Alternatively, correlate the probe timestamps with real-time location data provided by the railway company. Cheers, -- Simon.